1. Field of the Invention
The present invention relates to novel organo-platinum complexes and an anti-tumor composition containing at least one of the complexes as an effective ingredient therefor.
2. Related Arts
It has been known that certain organo-platinum complexes show an anti-tumor activity. Since the fact that cis-dichlorodiamine platinum (II) (General term: Cisplatin) has anti-tumor activity was reported by B. Rosenberg et al ["Nature" Vol. 222, page 385 (1969)], various studies have been energitically made to develop various organo-platinum complexes per se or to establish a new chemotherapy system on tumors and more particularly cancers. As a result, for instance, following organo-platinum complexes have been proposed.
(a) Malonato(1,2-diaminocyclohexane)platinum (II) [Jap. Pat. No. 53-31648 (A)], PA0 (b) Sulfato(1,2-diaminocyclohexane)platinum (II) [Jap. Pat. No. 54-44620 (A)], PA0 (c) 4-Carboxyphthalato(1,2-diaminocyclohexane)platinum (II) [Jap. Pat. No. 54-46752 (A)], and PA0 (d) cis-Dichloro-trans-dihydroxy-bis(isopropylamine)platinum (II) [Jap. Pat. No. 54-77694 (A)].
Each of such known organo-platinum complexes has advantages of showing an excellent anti-tumor action, having a wide anti-tumor spectrum and having a good solubility to water, but shows a disadvantage of having a relatively high side effect. For instance, the Cisplatin which is one of examplar conventional organo-platinum complexes shows a high nephrotoxicity, may accompany a violent nausea or vomiting, when the complex is dosed, and eventually causes dysacousis.
In order to suppress a generation of such side effects, and more particularly the nephrotoxicity or reduce a symptom due to this side effect, hitherto, various measures have been adopted in dosing manner of the organo-platinum complex, for instance the Cisplatin was mixed with mannitol, dextrose or the like, or dosed together with a diuretic drug such as phlocemide. However, each of such measures is a passive one and is not preferable, since its effect will be influenced by difference in each individual.